Embodiments of the system relate generally to a field of voltage regulation and more specifically to a load tap changer for power delivery.
Electricity is supplied to consumers through a power grid at a very high voltage to reduce energy losses during transmission. The increasing use of distributed and renewable-based generation in the power grid requires more flexibility in network voltage regulation. Transformers have been classically used to scale the network voltage allowing efficient transmission and distribution of power. Nevertheless, their use as a tool for voltage regulation was limited mainly due to the large cost implications, which did not match the otherwise relatively lower cost of power transformers.
For regulating the output voltage of transformers, on-load and off-load tap changers are available in the market. Off-load tap changers are low cost, but require disconnecting the entire load from the transformer prior to each single operation. There are two types of on-load tap changers, mechanical and electronic. Mechanical on-load tap changers allow for in-service operation, but have demanding mechanical requirements making the tap changer large, heavy, and expensive. The maintenance requirements of mechanical components in mechanical on-load tap changers limit the number of tap changes allowed in a lifetime of the tap changer. For this reason, their use is limited to relatively few points in the network, and to a slow voltage variation correction.
The main drawback of mechanical on-load tap changers is unavoidable arcing between two contact terminals when a tap is changed. Electronic on-load tap changers on the other hand do have mechanical contacts but reduce the arcing during tap changing operation by use of semiconductor devices which further reduce maintenance requirements as compared to mechanical on-load tap changers. However, electronic on-load tap changers have higher cost due to the cost of semiconductor switches utilized in the tap changers.
For these and other reasons, there is a need for an improved load tap changer.